Television apparatus



' April 16, 1935f p. VON- MIHALY TELEVI S I ON APPARATUS Filed April 4, 1932 l 5 Sheets-Sheet 1 April 16, 1935.

D. VON MIHALY 1,998,347

TELEVISION APPARATUS Filed April 4, 1932 5 Sheets-Sheet 2 7 a WW April 16, 1935. D. VON MIHALY 1,998,347

TELEVISION APPARATUS 7 Filed April 4, 1952 5 Sheets-Sheet 3 /h vemor'k gwg mmwamw April 16, 1935.

D. VON MIHALY TELEVISION APPARATUS Filed A ril 4, 19:52

5 Sheets-Sheet 4 A April 1935- D. VON MIHALY A 1,998,347

TELEVISION APPARATUS Filed April 4, v1932 5 Sheets-Sheet I 5 In VENZ'OIJ holes.

Patented Apr. 16, 1935 UNITED stars,

1,998,347 TELEVISION APPARATUS 1 Dnes vonlviihaly, Berlin-Wilmemdorf, Germany, assignor to the firm I. M. K. Syndicate'Limited;

London, England Application April 4, 1932, Serial No. 602,972 In Germany April 14, 1931 29 Claims.

My invention relates to television apparatus for splitting up or recombining pictures.

A preferred type of splitting-up or recombining member is a disk having spirally arranged This type is preferred on account ofits simplicity and cheapness.

Spiral-hole disks as made at present are of sheet metal .1 to .2 millimetres thick and their holes are pitched uniformly along a spiral. When the disk is rotated in the plane of the picture each hole moves along a row of picture spots and the. sum of the spots appearing through the holes makes up the, complete picture.

There are certain difficulties about the operation of spiral disks in practice. One of them is due to the smallness of their holes. The holes move on arcs of a circle and therefore it is desirable that the curvature of their inner and outer edges should approximately be curved to the same radius as the arcs.- This, however, is hardly practicable on account of the smallness of the holes.

Take for instance, the normal size of pictures,

30 by 46 millimetres; Splitting up this picture into 30 lines requires 30 holes at one sq.-millimetrepitched millimetres apart. The perimeter of the disk is 1260 millimetres, and its diameter 380 millimeters. This size is rather inconvenient and so large a disk obviously requires much energy for rotating it. The energy required for synchronization is also considerable lines with the same area of picture spots would require a diskoi 1600 millimetres diameter. With a diameter of 200 millimetres, the area of the holes would be .04 sq. millimetres and such holes could notbe made with the degree of exactitude required. h

It has been attempted to make disks in which the holes were replaced by transparent spots ob tained by photographic means but such a disk,

could be made only of glass or celluloid and, could not bethicker than ;01 to .02 millimetres, with consideration of light refraction and assimila-tion. Glass disks of such thinness are too fragile while celluloid disks are not rigid enough.

Other known means for splitting up and recombiningpictures also possess certain poor features. Thus, the mirror wheel requires such a 5, degree of precision and is therefore so expensive, and the energy required for rotation and synchroniaation'is so great thatfit could not be used for an instrument to be universallyadopted. Nor are oscillographs satisfactory. The cathoderay oscillograph requires very complicated electric auxiliaries and double synchronization and is not suitable for the direct transmission of the images of objects. Conditions are more favorable in the elect'rodynamic oscillograph but this instrument has the drawbacks that the splittingup is effected in a. meandering line and that comparatively complicated optical auxiliaries. are required. f

' Itis an object of my invention to eliminate the drawbacks of the existing splitting-up and recombining" means and .toflprovicle instrument which is smaller than the existing ones, requ'ires less power for operationand synchronization and effects very fine splitting-up. 25

To this end, I combine a fixed member for splitting upo'r' recombining, the pictures, which may be a drum with holes arranged in a helical, or a fiat disk with holes arranged in a spiral line, with a rotary mirror which projects the pictures onto the splitting-up, ire-receives them-from the recombining member, as the case may be.

The member is heldin a fixed position with" respectto-the rotary mirror but maybe adjusted by turning about its axis for correcting phase 35v distortion. Q

The rotary mirror may be arranged on the shaft of a phonical wheel by which it is rotated.

It is still another objectof my invention to'increase the light intensity of the picture spots. To this end, I provide a second rotary mirror in combination with a reflector. The second mirror rotates in synchronism with the first mirror. The picture spots "from the second mirror are reflected onto aphoto-electric .cell or, formcombining the pictures, the light of a; glow lamp is reflected onto the second mirror by the refiector.

It is still another object of my invention to provide a splitting-up or recombining member which may be adjusted for various numbers of holes or transparent-spots, andfor'various positions of the holes or spots on the perimeter'of thebarrel.

In the accompanying drawings apparatus em bodying my invention are illustrated diagrammatically by way of example.

In the drawings Fig. 1 is a perspective illustration, and

Fig. 2 is an axial section, of an apparatus having a drum-shaped splitting-up member,

Fig. 3 is an end elevation of the apparatus, showing a pair of curved photo-electric cells at the sides of the barrel,

Fig. e is an axial section of an apparatus as shown in Figs. 1 and 2, equipped with a rotary prism for compensating the rotation of the pictures,

Fig. 5 is an axial section of an apparatus having a second rotary mirror with a reflector,

Fig. 6 is a side elevation and Fig. '7 is an end elevation, viewed from the left in Fig. 6, of an element for a built-up drum,

Fig. 8 is an end elevation of the drum built up from the elements in Figs. 6 and '7,

Fig. 9 shows the two parts of a drum which is built up from a pair of sleeves, and

Fig. 10 is an axial section of an apparatus having a fiat disc with holes arranged in a spiral instead of a drum with holes arranged in a helical line.

Fig.'l1 shows a detail of the optical part.

Referring now to the drawings, and first to Figs. 1 and 2, l is the object to be imaged, 2 is an objective and 3 is a rotary mirror onto which the image of the object I is projected. The mirror which may also be a prism or any other reflecting member, is at an angle of 45 degs. to the optical axis of the objective 2 and is rotated about the axis by a motor or any suitable other driving means 4. Gis a drum-shaped splitting-up or recombining member which is fixed with respect to the rotary mirror 3 and concentric to the optical axis of the objective 2. The drum has a helical row of holes 5.

The image i of the object I is projected onto the inner wall of the drum 6, moves along the drum wall and is split up by the holes 5. 1 and 8, Fig. 3, are photo-electric cells at the sides of the barrel 6 which are curved to its radius. The cells are illuminated by the picture spots through the holes 5 and the light impulses are translated into current impulses by the cells.

Thesame apparatus may also be used for recombining pictures if the photo-electric cells 1, 8 are replaced by glow lamps. The picture spots formed by the holes 5 are successively projected into the objective 2 by the rotary mirror 3 and combined into a picture.

The advantages of this apparatus for splitting up or recombining pictures are numerous and important.

First and foremost, it is not necessary to rotate the member 6, the only movable part being the mirror 3, with its loW weight and negligible windage. In order to reduce the windage still further the mirror 3 may be arranged in a vacuum chamber (not shown) as already suggested for spiralhole disks which, however, present considerable difiiculties on account of the large diameter of the disks.

The power demand of my apparatus is very low and so is the energy required for synchronization.

The apparatus is quite symmetrical and there is no distortion of the split-up or recombined pictures but the pictures remain perfectly square.

Another important advantage is that due tothe fixed arrangement of the drum 6 in determining the size of thedrum it is not necessary to consider its 'easy rumiing so that it may be comparatively heavy which favours the exactitude of the holes 5. It will be understood that as weight is no longer a consideration the drum may be built up from comparatively heavy and numerous elements and high exactitude of the holes obtained, as will be described with reference to Figs. 6 to 8.

In apparatus as described with reference to Figs. 1 to 3, the same apparatus may be used for splitting up and recombining pictures without making any change therein, except substituting the photo-electric cell or cells by a glow lamp. If, however, the pictures are split up by an apparatus of other type, and only recombined by my apparatus, means must be provided for compensating the rotation of the picture with the rotary mirror 3. This rotation will occur under all conditions, but is troublesome only if my apparatus is not used for splitting up and recombining. If my apparatus is used for both operations the rotary mirrors at the sender and the receiver compensate each others rotation.

In other cases, compensation means must be provided, and an example is shown in Fig. 4,

which shows a receiver designed as described with reference to Figs. 1 to 3. 9 is a triangular prism arranged intermediate the mirror 3 and the objective 2. The prism 9 rotates at half the speed of the mirror 3, and then has the effect of another mirror rotating in the opposite direction. Any other suitable optical means, such as a mirror, a system of lenses and the like (not shown) may be provided instead of the prism 9. The prism 3 and the prism 9 can be driven by the same phonic wheel having two pole wheels the one of them having half the number of poles of the other one. In this case (not shown) .the pole wheels are connected to concentrical hollow shafts and the mirror is arranged within and fixed to the inner shaft while the prism is fixed to the outer shaft which belongs to the pole wheel having the greater number of poles and therefore, is rotating with half thespeed of the inner shaft.

In the apparatus described, it is not necessary that the area of the holes 5 should be equal to the area of the picture spots as the picture can be magnified or reduced as desired by the objective 2. Therefore the holes 5 may be as large as one sq. centimetre but their edges should be staggered for the width of the picture spots in the axial direction of the drum 6. The width or" the picture spots may be 1 millimetre, for example. This permits a very considerable increase of the light intensity as the intensity increases with the area of the holes, being, for instance, 100 times greater for a hole of one sq. centimetre than for one of one sq. millimetre.

Other means for increasing the intensity will be described with reference to Fig. 5. The apparatus described, with the drum 6, is surrounded by a conical reflector 22. 23 is a similar reflector arranged in line with reflector 22, and 24 is a second mirror which rotates in synchronism with the first mirror 3, being preferably arranged on the same shaft at the opposite side of motor 4. 25 is a condenser in the extension of the optical axis, and 25 is a photo-electric cell. I

The light rays passing through holes 5 are refiected onto the reflector 22 by the first mirror 3,0nto the reflector 23 by the reflector 22, onto the mirror 24 by the reflector 23, and onto the cell 26 by the mirror 24.,

The same apparatus may be used for recombining pictures by replacing the cell 26 by a scribed with reference to Figs. 6, 7 and 8. I8-

is one of the elements which may beof steel. Suppose that the size of the holes H in each element ill is to beuOl sq. millimetre, then the width of each element as well as the width of the hole or slot H is .l millimetre. For a drum having'S holes at .ill sq. millimetre, 48 elements 5 3 are, pitched at an angle of 7 A,; degs. for which purpose they are equipped with an indexing projection E2. The several elements are placed in a frame as shown in Fig. 8, with end rings l3 and bolts M for holding them assembled. The diameter of this drum, at 4800 picture spots, is only 150 millimetres. any thickness may be employed. Thus, with elements .01 millimetre thick, holes of .001 sq. millimetre, with a correspondingly smaller diameter of the drum, will be obtained. The exactitude is by no means reduced by this as punching the slots ii in the rings is not difficult and the holes are exactly bordered by the edges of the slots and by the sides of the adjacent elements Ill. Defiection phenomena are eliminated by gradually widening the slots H in the direction of the perimeter of element Ill, as shown in Fig. 6. The holes in this manner have practically no Wall thickness. Assembling the drum may be facilitated by placing the barrel on a glass templet, and inspecting the position of the holes by means of a source of light in the templet.

Drums built up in the manner described have the advantage that the arrangement of their holes canv be altered at any time by adding or removing elements. In order to save the trouble of adjusting the holes as often as an alteration is required, the elements may be made for several pitches. Thus, a drum may have 78 rings or elements, 30 of which are for pictures at 30 lines, and the remaining 48 for'pictures at 48 lines.

The drum is placed in position by shifting it axiv extend in parallel to its axis and may be made by etching. H is a sleeve which is placed on the drum l5 and has a helical slot l8 which may also be etched. The two slots lay open a-row of holes in helical arrangement which are not square but supplement each other. I

Referring now to Fig. 10, 20 is a flat disk with spiral holes 21 onto which the light is projected from mirror 3 by means of a tapered reflector is, as indicated by the arrows. This type of apparatus is alsovery small, since the disk 26 is fixed and not movable, and so may be made of a very thin glass plate, with the holes 2! made by photographic means.

The holes 5 might also be made photographically, as well as the slots 16 and I8 (Fig. 9).

Obviously, elements ofwheel rotating the prism 9 which is arranged in the centre of the rotor. The stator; 28 of the phonicwheel is fixed to the frame 21. Another. phonic Wheel 3| :is driving the rotary mirror or prism 29 arranged-in the centre of the scanning drum 33 which is encircled by a photocell or glow lamp-32. a

I claim: 1. Television apparatus comprising a stationary drum having a plurality of analyzing elements for analyzing or recombining an image thereon in circumferentially spaced relation, and a reflecting means mounted within said drum for rotation about the axis thereof and cooperating with said elements for scanning.

2. Television apparatus comprising movable reflecting means for causing a complete image to move along a path and a plurality of stationary analyzing elements in said path spaced longispaced from said analyzing means to reflect an' image formed by said objective upon said analyzing means. I

5., Television apparatus comprising a plurality of stationary analyzing elements, and means rotating about an axis to reflect a picture arranged in said axis to said analyzing elements, said elements being circumferentially spaced'around said axis.

6. Television apparatus, comprising .av rotary reflecting means, a plurality of stationary analyzing elements for analyzing or recombining an image circumferentially spaced around the: axis of said means, said meanscooperating with said elements for scanning, an objective in the axisof rotation of said rotary means, and light deflecting means between said objective and said rotary means to prevent rotation of said image by the rotary means. I I a '7. Television apparatus, comprising a rotary reflecting means, a plurality of stationary analyzing elements for analyzing or recombining an image circumferentially spaced around the axis of said means, said means cooperating with said elements for scanning, an objective in the axis of rotation of said rotary means, anda prism-rotatably mounted between said objective and said means. l

. 8. Television apparatus, comprising a rotary reflecting means, a plurality of stationary analyzing elements for analyzing or recombining an image circumferentially spaced around the axis of saidmeans, said means cooperating with said and means to rotate said prism at half the speed of rotation-of said rotary means. v

9. Television apparatus comprising a fixed drum having a helical rowof apertures for splitting up or recombining the pictures, a rotary refleeting member cooperating with said drum and an objective arranged in the axis of rotation of said rotary member. s

10. Television apparatus comprising the combination of a stationary drum provided with helically disposed spaced apertures for analyzing or recombining an image, and a coaxial rotary reflecting member cooperating with said apertures for scanning.

11. Television apparatus comprising the combination of a stationary drum provided with helically disposed spaced apertures for analyzing or recombining an image, coaxial rotary reflecting means cooperating with said apertures for scanning, and electrooptical translating means exposed thereto through said apertures.

12. Television apparatus comprising the combination of a fixed drum provided with helically disposed spaced apertures for analyzing an image, coaxial rotary reflecting means cooperating with said apertures for scanning, and light sensitive electric cell means exposed thereto through said apertures.

13. Television apparatus comprising the combination of a fixed drum provided with helically disposed spaced apertures for recombining an image, coaxial rotary reflecting means cooperating with said apertures for scanning, and electrically responsive light valve means exposed thereto through said apertures.

14. Television apparatus comprising a' fixed drum having a helical row of apertures for splitting up the pictures, a rotary reflecting member cooperating with said drum, an objective arranged in the axis of rotation of said rotary member, and a photo-electric cell arranged outside said drum and curved to its radius.

15. Television apparatus comprising a fixed drum having a helical row of apertures for re combining the pictures, a rotary reflecting member cooperating with said drum, an objective arranged in the axis of rotation ofsaid rotary member and aglow lamp arranged outside said drum and curved to its radius.

16. Television apparatus comprising a fixed disc having spiral rows of apertures for splitting up or recombining the pictures, a rotary reflecting member and an objective arranged in the axis of said disc, and a conical reflector adapted to reflect the light rays from said rotary member to said disc.

1'7. Television apparatus comprising the combination of a stationary disc provided with 'spirally disposed spaced apertur s for analyzing or recombining an image, a coaxial rotary reflecting member, and a conical reflector adapted to establish optical paths between said rotary reflector and said apertures successively.

18. Television apparatus comprising, in combination, a fixed drum provided with helically disposed spaced apertures for analyzing or recombining an image, and, coaxial therewith, a reflector rotatable within said drum, a conical reflector surrounding the drum, axconical reflector opposed to the first, and a second reflector rotatable synchronously with the first, for establishing optical paths through successive apertures between the rotary reflector within said drum and an eiectrooptical translating device.

19. Television apparatus comprising a fixed drum having a helical row of apertures for splitting up the pictures, a rotary reflecting member, and an objective arranged in the axis of said drum, a conical reflector surrounding said drum, a second rotary reflecting member rotating in synchronismwith said first mentioned reflecting member, a second conical reflector adapted to reflect the light rays from the first conical reflector to the second rotary member, and a photocell adapted to receive the light rays from said second rotary reflecting member.

20. Television apparatus comprising a fixed drum having a helical row of apertures for recombining the picture, a rotary reflecting member and an objective in the axis of said drum, a conical reflector surrounding said drum, a glow lamp, a second rotary member rotating in synchronism with the first mentioned rotary member, and a second conical reflector adapted to reflect light rays of the glow lamp from the second rotary member to the first said conical reflector and onto the first mentioned rotary member.

21. Television apparatus according to claim 20 wherein both rotary reflecting members are driven by the same phonic wheel arranged between them.

22. Television apparatus according to claim 1, wherein the apertures of said drum have a larger area than the picture spots and are successively displaced axially of said drum the width of a picture spot.

23. Television apparatus comprising the combination of a fixed member having a plurality of spaced means for analyzing or recombining an image, a rotary reflecting member cooperating therewith for scanning, an objective cooperating with said rotary member, a rotary triangular prism interposed between said rotary member and said objective, a phonic wheel for driving said rotary member, and a phonic wheel for driving said prism at half the speed of said rotary member.

24. Television apparatus according to claim 23 wherein the rotary triangular prism is arranged between the lensesof the objective in the centre of the rotor of a phonic wheel adapted to rotate said prism.

25. Television'apparatus according to claim 1 wherein the drum is provided with several helical rows of apertures at different distances, said drum being adapted to be shifted axially so that any of the rows can be brought into cooperation with said rotary reflecting member.

26. Television apparatus according to claim 1, wherein the drum is built up from ring-shaped elements, each element having a slit the width of which is substantially equal to the thickness of the elements.

27. Television'apparatus according to claim 1, wherein the drum is built up from ring-shaped elements, each element having a slit the width of which at the inner perimeter of the element being substantially equal to the thickness of the element and increasing from there to the outer perimeter of the element.

28. Television apparatus according to claim 1, wherein the fixed drum consists of two opaque cylindrical parts, fitting in one another, one of them being provided with transparent slots extending in parallel to its axis, and the other one being provided with a transparent helical slot.

29. Television apparatus according to claim 1, wherein the drum is adjustable in circumferential direction.

w DENES VON MIHALY'. 

